The induction of volatile organic compounds (VOCs) in plants has gone virtually unexamined, despite evidence that induction of plant volatiles is dependent on the interactions of biotic factors, such as plant hormones (de Bruxelles and Roberts, 2001; Ament et al., 2004), herbivore-derived elicitors (Spiteller and Boland 2003), and associated microorganisms including pathogens (Preston et al., 1999; Cardoza et al., 2002), as well as abiotic factors, such as wounding (Mithofer et al., 2005), heavy metals (Mithofer et al., 2004), and temperature and light (Takabayashi et al., 1994). Plant growth promoting rhizobacteria (PGPR) represent a wide range of root-colonizing bacteria whose application often is associated with increased rates of plant growth (Kloepper, 1992; Zehnder et al., 1997), suppression of soil pathogens (Schippers et al., 1987), and the induction of systemic resistance against insect pests (Kloepper et al., 1999; Ryu et al., 2004). The lack of research on induction of VOCs in plants and whether PGPR can influence production of VOCs in plants is surprising given that PGPR are increasingly being applied in the production of several field crops in some parts of the world (Backman et al., 1997; Cleyet-Marcel et al., 2001). Backman et al. (1997) reported that 60-75% of the US cotton crop is treated with the PGPR product Kodiak®, a Bacillus subtilis product used for suppression of Fusarium and Rhizoctonia soil pathogens. Here, the potential effects of PGPR on induction of cotton volatiles and consequences for attraction cotton herbivores and their parasitoids were studied. Surprisingly, PGPR were observed to elicit changes in plant VOC's with important ramifications. Knowledge of the effects of PGPR on the induction of plant volatiles and insect-plant interactions will likely contribute to the increased adoption of PGPR products and development of better products and also mitigate against potential negative impacts of these products.